[Antimicrobial resistance and genomic characterization of Campylobacter isolates recovered from retailed poultry meat samples in 20 provinces of China in 2020]

Objective: To understand the antimicrobial resistance and genome characteristics of Campylobacter isolates recovered from retailed poultry meat samples in 20 provinces in China in 2020. Methods: In 2020, 265 Campylobacter strains including 244 Campylobacter jejuni and 21 Campylobacter coli collected from retailed poultry meat samples in China were tested for antimicrobial resistance to 9 antimicrobial compounds by using the agar dilution method. Forty-two selected isolates were sent for whole genome sequencing and 38 high-quality genomes were analyzed for their antimicrobial resistance genes, virulence genes, sequence types and genetic diversity. Results: The resistance rates of Campylobacter isolates from poultry meats to tetracycline, nalidixic acid and ciprofloxacin were the highest (84%-100%), with 53.2% of the isolates showing multidrug resistance in this study. The resistance rates of C. coli to erythromycin, azithromycin, telithromycin, gentamicin and clindamycin were significantly higher than those of C. jejuni (P<0.05). The resistance genes conferring resistance to β-lactams (100%, 38/38), quinolones (94.7%, 36/38), tetracycline (81.6%, 31/38) and aminoglycosides (50%, 19/38) were the most frequently detected among 38 Campylobacter genomes. C. jejuni carried more virulence genes than C. coli. In total, 19 and 17 sequence types (ST) were obtained from 20 sequenced C. jejuni and 18 C. coli isolates, respectively, including 5 novel STs. The isolates showed a high genetic diversity based on their sequence types. Conclusion: The phenomenon of antimicrobial resistance in Campylobacter from poultry meat sources in China is relatively serious, and resistance and virulence genes are widely distributed in Campylobacter. There is genetic diversity in Campylobacter.

[Research progress on the drug-resistant mechanism and foodborne transmission of Enterococcus species]

Enterococcus species are important opportunistic pathogens that are associated with nosocomial-and community-invasive infections. Currently, drug-resistant enterococcal isolates are challenging nosocomial Enterococci species with limited antimicrobial therapeutic options being available to treat these infections. Moreover, the ability of enterococci to act as reservoirs of antibiotic resistance genes within the food chain poses an important food safety risk. In this paper, we reviewed the new development of the pathogenicity and drug-resistance and its mechanism of Enterococcus species, and also drug-resistance of foodborne Enterococcus species spreading in human and livestock. And then, we proposed the ways to control and decrease the drug-resistance of foodborne Enterococcus species.

[Antimicrobial susceptibility and drug-resistance genes of Yersinia spp. of retailed poultry in 4 provinces of China]

Objective: To monitor the antimicrobial resistance and drug-resistance genes of Yersinia enterocolitis, Y. intermedia and Y. frederiksenii recovered from retailed fresh poultry of 4 provinces of China. Methods: The susceptibility of 25 isolated Yersinia spp. to 14 classes and 25 kinds of antibiotics was determined by broth microdilution method according to CLSI (Clinical and Laboratory Standards Institute). The antibiotic resistance genes were predicted with antibiotic resistance genes database (ARDB) using whole genome sequences of Yersinia spp. Results: In all 22 Y. enterocolitis tested, 63.7% (14 isolates), 22.8% (5 isolates), 4.6% and 4.6% of 1 isolates exhibited the resistance to cefoxitin, ampicillin-sulbactam, nitrofurantoin and trimethoprim-sulfamethoxazole, respectively. All the 25 isolates were multi-drug resistant to more than 3 antibiotics, while 64.0% of isolates were resistant to more than 4 antibiotics. A few Y. enterocolitis isolates of this study were intermediate to ceftriaxone and ciprofloxacin. Most Yersinia spp. isolates contained antibiotic resistance genes mdtG, ksgA, bacA, blaA, rosAB and acrB, and 5 isolates recovered from fresh chicken also contained dfrA1, catB2 and ant3ia. Conclusion: The multi-drug resistant Yersinia spp. isolated from retailed fresh poultry is very serious in the 4 provinces of China, and their contained many kinds of drug-resistance genes.

[Serotype distribution and antimicrobial resistance of Salmonella isolates from retail chicken carcasses in six provinces of China]

Objective: To obtain the serotype diversity and antimicrobial resistance of Salmonella isolates recovered from retail chicken carcasses for sale in six regions of China. Methods: From August 2010 to March 2012, each month 20 retail chicken carcasses including freshly slaughtered, chilled and frozen samples were collected from supermarkets and farmer's markets in 7 monitoring sites in Beijing, Jilin province, Inner Mongolia Autonomous, Shanxi province, Jiangsu province and Guangdong province, respectively. Samples were routinely collected for 12 months for each site. 1 680 chicken carcasses were collected in total and 2 629 Salmonella strains were isolated by PCR and biochemical method. Luminex xMAP method and classical slide agglutination method were carried out to determine isolates' serotypes. Minimal inhibitory concentrations (MICs) of 10 classes of antimicrobials including 14 agents were determined using broth micro-dilution method. Mocular methods were used to determine antimicrobial resistance genes of CIP-CTX-CT co-resistant isolates. Results: In all, 2 629 Salmonella isolates, there were 17 seorgroups and 58 serotypes, B and D1 were the dominant serogroups with rates of 34.7% (n=913) and 31.0% (n=815), Enteritidis (30.8%, n=810), Indiana (17.6%, n=463), Infantis (10.6%, n=278) were the top three serovars. We found 224 CIP-CTX co-resistant S. Indiana containing 3 colistin resistant strains, one of them carrying mcr-1 gene and being ESBLs positive, which demonstrated a nine multi drug resistance against 11 antimicrobials tested. Conclusion: These data began to describe the complicated serovar diversity and heavy antimicrobial resistance of Salmonella isolates recovered from retail chicken carcasses in six regions of China. The findings highlight the emergence of ciprofloxacin and cefotaxime co-resistant S. Indiana and also a mcr-1 positive S. Indiana with heavy multi drug resistance.

[The evaluation and surgical treatment of mass in the pretracheal space]

OBJECTIVE

To study the pathological and clinical features and the surgical results of the mass in the pretracheal space.

METHODS

From 1999 to 2004, 8 females and 3 males with an average of 43 years (from 32 to 61 years) were included CT scan, nuclear imaging, ultrasound and ultrasound-guided aspiration, endoscopic and laboratory measure were used in the evaluation for the masses before operation. Complete removal of mass was carried out in all patients under general anesthesia, and continuous negative pressure draining was routinely used.

RESULTS

Six masses with firm consistency could be moved easily transversely, but slightly moveable with swallowing. On contrast CT or ultrasound, all the masses had clear circumscription and showed rounded or lobular shape. No hemorrhage, chylous or lymph leakage, or recurrent laryngeal injury was encountered. Goiter was found in 6 cases, parathyroid adenoma in 2 cases, and thymoma, parathyroid cyst or lymphatic cyst was diagnosed in the rest three patients respectively. No recurrence was found with the following-up of 7 - 42 months.

CONCLUSIONS

Goiter, parathyroid adenoma and thymoma were common lesions presenting as mass in the pretracheal space and surgically curable without complications.

[Surgical management of primary hyperthyroidism and coexistent thyroid carcinoma]

OBJECTIVE

To evaluated the results of surgical treatment for primary hyperparathyroidism coexistent with thyroid cancer.

METHODS

From March 2007 to May 2014, 27 patients suffered thyroid carcinoma coexistent with primary hyperparathyroidism with pathological and laboratory confirmation were studied retrospectively. In 8 of 27 cases thyroidectomy and parathyroidectomy were performed separately, with interval time of 3 to 26 months, and in the remaining cases both procedures were done simultaneously. During surgery quick PTH evaluation and calcium measure were routinely performed.

RESULTS

Postoperative temporary hypoparathyroidism was found in 26 of 27 cases, and postoperative permanent hypoparathyroidism developed in 4 cases that underwent separate operation. Limited movement of vocal cord was showed in 4 cases after parathyroidectomy, but it lasted no more than 2 months. No permanent paralysis of recurrent laryngeal nerve was found. No thyroid cancer or hyperparathyroidism was found with follows-up of 11 to 43 months.

CONCLUSIONS

Thyroidectomy and parathyroidectomy performed separately have higher risk to develop hypoparathyroidism than they are done simultaneously. PTH and calcium should be evaluated in patients with thyroid carcinoma whenever available.

A DNA vaccine encoding a cell-surface protein antigen of Streptococcus mutans protects gnotobiotic rats from caries

A cell-surface protein antigen (PAc) of Streptococcus mutans is considered a virulence factor because it may mediate initial attachment of Streptococcus mutans to tooth surfaces. Thus, inhibiting PAc is predicted to provide protection against caries. To develop vaccines against dental caries, we constructed a DNA vaccine, pCIA-P, which encodes two high-conservative regions of PAc. Expression of the recombinant protein was obtained in eukaryotic cells in vitro and in vivo. In this report, we provide evidence that fewer caries lesions, and high levels of PAc-specific salivary IgA antibody and serum IgG antibody, were observed in gnotobiotic rats following targeted salivary gland (TSG) administration of pCIA-P. This study shows that the recombinant DNA vaccine pCIA-P could induce protective anti-caries immune responses and that TSG immunization is a promising strategy for the inhibition of dental caries.